Systems and methods of removing and managing heavy metals

ABSTRACT

Systems and methods remove and manage heavy metals. In one implementation, an exemplary method can be applied to food processing and food consumption to remove heavy metals such as mercury, lead, uranium and cadmium before absorption by a living organism. The exemplary method exposes the food to a heavy-metal binding ligand, such as a concentrated protein or phytic acid, to form a heavy-metal chelate, and then allows the chelate to separate from the food. In another implementation, an exemplary probe possesses innovative molecular layers on its surface to detect and quantify heavy metals by attracting and binding traces of the heavy metals on a ligand layer.

RELATED APPLICATIONS

This patent application is a divisional application claiming the benefitof priority to pending U.S. patent application Ser. No. 12/134,955 toSchwartz, filed Jun. 6, 2008 and incorporated herein by reference, whichin turn claims priority to U.S. Provisional Patent Application No.60/933,640 to Schwartz, filed Jun. 7, 2007, and entitled, “Method ofRemoving and Managing Heavy Metals,” which is incorporated herein byreference.

BACKGROUND

Some metals, such as iron, cobalt, copper and zinc are beneficial toorganisms in very low concentrations. But excess amounts of these metalsmay be detrimental and eventually toxic to organisms, even when theirconcentration is still low. Other heavy metals, such as mercury, lead,and cadmium, have no known nutritional benefit to organisms, andbioaccumulations of such heavy metals cause adverse health effects.

Heavy metals, such as mercury and lead for example, cannot bemetabolized by the body and if accumulated in the body, cause toxiceffects by interfering with physiological functions. Yet heavy metalsare found everywhere in the environment because they are naturally partof the earth's crust. Moreover, metallic elements, such as cadmium,chromium, copper, lead, mercury, nickel, and zinc are used tomanufacture products and are present in some industrial, municipal, andurban runoff as they are used in coatings, paints, lacquers forpackaging, toys, furniture, etc. They do not break down or decompose andtend to build up in plants, animals, and people. Thus, they enter livingorganisms via food, drinking water, and air. Further, removal of heavymetals from organisms is conventionally a difficult process.

SUMMARY

Systems and methods remove and manage heavy metals. In oneimplementation, an exemplary method can be applied to food processingand food consumption to remove heavy metals such as mercury, lead,uranium and cadmium before absorption by a living organism. Theexemplary method exposes the food to a heavy-metal binding ligand, suchas a concentrated protein or phytic acid, to form a heavy-metal chelate,and then allows the chelate to separate from the food. In anotherimplementation, an exemplary probe possesses innovative molecular layerson its surface to detect and quantify heavy metals by attracting andbinding traces of the heavy metals on a ligand layer.

This summary section is not intended to give a full description of thesystems and methods for removing and managing heavy metals, or toprovide a list of features and elements. A detailed description ofexample embodiments follows.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flow diagram of an exemplary process for removing heavymetals from fish;

FIG. 2 is a flow diagram of an exemplary process for removing heavymetals from a surface of an object;

FIG. 3 is section view of a submarine water intake and exemplaryheavy-metal filtration system;

FIG. 4 is a flow diagram of an exemplary heavy-metal absorptionprevention method;

FIG. 5 is a perspective view of an exemplary measuring probe fordetecting and quantifying heavy metals;

FIG. 6 is a flow diagram of an exemplary method of measuring heavymetals;

FIG. 7 is a diagram of an exemplary nano-based sensor for detecting andquantifying heavy metals;

FIG. 8 is a diagram of binding a heavy metal in an intestine of a livingorganism to prevent absorption of the heavy metal by the organism;

FIG. 9 is a diagram summarizing results of an experiment preventingliving organisms from absorbing mercury.

DETAILED DESCRIPTION

Overview

This disclosure describes systems and methods for removing and managingheavy metals. As used herein, the term “heavy metal” refers to a memberof the dense, higher atomic weight elements that have metallicproperties at room temperature. “Heavy metals” include at least cadmium,chromium, copper, lead, manganese, mercury, nickel, zinc, barium,selenium, and silver, which tend to be toxic in low concentrations andtend to accumulate in the food chain. For purposes of the innovativetechniques to be described below, “heavy metals” may also include iron,aluminum, tin, cobalt, gallium, lithium, arsenic, beryllium, vanadium,and even other metals and metalloids. The heavy metal mercury isselected as a representative example for describing the innovativeremoval and management techniques to be described below. The subjectmatter described, however, is applicable to many metals.

In one implementation, an exemplary method prevents the absorption ofheavy metals by bonding a substance to heavy metal atoms. The resultingbonded substance has properties which allow the bonded heavy metal atomsto be removed, passed, or managed, depending on circumstance. Theligating substance may be a concentrated form of a protein, such as alegume protein, a pulse legume protein, a vegetable protein, a grainprotein, etc. Other ligands are also described below. In oneimplementation, a particular ligand can be selected to target specificmetals, such as mercury, or a select group of metals and their ions,such as mercury, lead, uranium, and cadmium.

In various implementations, the exemplary systems and methods utilizethe process of chelation for detecting, removing, and managing heavymetals. For example, an exemplary probe assembly to be described belowuses innovative molecular layers to attract and bind heavy metals, fortheir detection and quantification.

In another implementation, a food processing method uses a concentratedprotein ligand, a phytic acid ligand, etc., to detoxify fish food fromheavy metals, e.g., fish food for fish raised in aquaculture forcommercial production and ultimately for human consumption. Theexemplary food processing method can also be applied to pet food, suchas cat food, dog food, bird food, and food directed toward wildliferescue, e.g., when a wildlife population is in danger from high levelsof heavy metal or other pollutants.

The exemplary food processing method may also be directed to human foodprocessing and food ingestion. For example, the exemplary method mayproduce a coating, sauce, or marinade to be eaten with fish or otherfood, that arrests absorption of mercury and other toxic species in thedigestive tract.

Certain exemplary ligands may be leveraged in processed foods toscavenge for mercury and other undesirable metals to prevent these frombeing absorbed in the body. Further, an ingestible form of exemplaryligands may be taken regularly in a diet to aid the body in riddingitself of heavy metals.

As used herein, chelation is a reversible process of bonding a ligand toa heavy metal ion. Ligand, as used herein, means a molecule, or amolecular group, that binds to another chemical entity to form acomplex. The resulting complex is referred to herein as chelate. Forexample, an exemplary method may form a chelate from the heavy metalmercury and the ligand. One example ligand is phytic acid, which hasfavorable characteristics that include availability and non-toxicity tohumans and the environment. Other common names and chemical nomenclatureof phytic acid include inositol hexakisphosphate, IP6, and “-phytate”(when in salt form). Phytic acid can be found within nuts, grains, seedsand is commercially available. Besides phytic acid, other ligands may beused in exemplary techniques including, EDTA(Ethylene-Diamine-Tetra-Acetic-Acid), BAL, DMSA (Dimercaptosuccinicacid), DMPS, CDTA, DTPA (Diethylene triamine pentaacetic acid), DPA,TETA (triethylenetetramine), NAC, TIRON, FRO, TRIEN, organic acids, andbacterial metalloregulatory protein (MerR).

The binding of phytic acid to mercury can be optimized for a givenremoval or management method. In general, for removal and management ofheavy metals, a phytic solution is created by placing phytic acid insolution with a fluid, such as water or other solvent. Phytic acid isslightly soluble in water. The solution is placed in contact withsurfaces contaminated with the heavy metal or in contact with food thatcontains undesirable heavy metal. The resulting chelate solution can bemoved to a location at which the chelate can be removed from thesolution and safely disposed of. The chelate can be filtered out of thesolution or sometimes removed via a magnetic process. It is alsopossible to break the bond between the mercury and the phytic acid via aheating process. This allows the mercury to be re-used for desirablepurposes.

Phytic acid has a strong binding coefficient for mercury. When presentwith mercury and other heavy metals, the phytic acid molecules have apreference for bonding with the mercury atoms over other heavy metalatoms. Therefore, in order to keep the phytic acid from removingdesirable metals, for example, calcium or metals of other mineralsbeneficial to the body (such as zinc, manganese, copper, molybdenum,magnesium and iron), in one implementation just enough phytic acid isplaced in solution to bond to an anticipated amount of mercury (e.g., aone-to-one ratio). That is, the concentration of phytic acid in thesolution is selected in a stoichiometric ratio to the anticipated amountof mercury.

The above-described general process will now be further described forspecific processes.

Food Processing Embodiment

Fish and shellfish are known to contain high levels of mercury due tothe accumulative process of biomagnification. Although the exemplarymethod is described in relation to processing fish and shellfish, theexemplary method is also applicable to processing other animal productsthat may contain undesirable levels of mercury or other heavy metals.

FIG. 1 shows an exemplary fish processing method 10, i.e., for fish thatcontain trace amounts of toxic heavy metals, such as mercury(“contaminated fish” 12). A solution 14 contains water and a selectedamount of phytic acid 16. During the soaking process 18, phytic acid 16bonds with mercury in the contaminated fish 12. Optionally, to place thephytic acid 16 deep into the tissue of the contaminated fish 12, it maybe desirable to create a vacuum within a container used for the soak 18prior to introducing the phytic acid solution 14, i.e., to perform thesoaking 18 under vacuum. As the vacuum is released, the phytic acidsolution 14 may more readily penetrate and permeate the entire tissue ofthe contaminated fish 12. After a sufficient amount of time has beenallowed for phytic acid 16 to permeate the entire fish bulk and bond tothe mercury within the contaminated fish 12, for example, from a fewseconds to many minutes depending on the granularity of the fish, thecontaminated fish 12 is put through a rinse 20, such as water. Theresulting water solution containing both the phytic acid solution 14 andthe chelate formed by the phytic acid 16 and the mercury of thecontaminated fish 12 can then be subjected to a separation treatment 22.Treatment 22 removes the chelate, which can then be disposed 24. Uponrinsing 20, the contaminated fish 12 is transformed into clean fish 26,meaning that the mercury or other heavy metal has been substantiallyreduced or removed. The clean fish 26 can then be put through itsconventional processing 28, which may include further treatments andrinses. In a variation, some steps of the conventional processing 28 mayalso be incorporated into the exemplary fish processing method 10.

In another implementation, an exemplary ligand such as a concentratedlegume protein, a concentrated pulse legume protein (e.g., derived fromyellow split peas), a concentrated vegetable protein, or a concentratedgrain protein, etc., is used as in the technique just described todetoxify fish food from heavy metals, e.g., to purify fish food for fishraised in aquaculture for commercial production and human consumption.The exemplary food processing method can also be applied to pet food,such as cat food, dog food, bird food, and food directed toward wildliferescue, e.g., when a wildlife population is in danger from high levelsof heavy metal or other pollutants.

The exemplary food processing method may also be directed to human foodprocessing and food ingestion. For example, the exemplary method mayproduce a coating, sauce, or marinade to be eaten with fish or otherfood, that arrests absorption of mercury and other toxic species in thedigestive tract.

Certain exemplary ligands may be leveraged in processed foods toscavenge for mercury and other undesirable metals to prevent these frombeing absorbed in the body. Further, an ingestible form of exemplaryligands may be taken regularly in a diet to aid the body in riddingitself of heavy metals.

Surface Treatment Embodiment

Object surfaces are susceptible to heavy metal contamination. Suchsurfaces include soil surfaces, surfaces of vessels in contact withseawater, such as submarines and ships, and food processing equipment.An exemplary surface treatment method 30 is shown in FIG. 2. Similar tothe fish processing method 10 described above, an amount of phytic acid36 is mixed into a solution 34. The resulting solution 34 is thenapplied to a contaminated surface at which the solution 34 is allowed tosoak 38 or is scrubbed into the surface creating a chelate between thephytic acid 36 and the mercury or other heavy metal. The resultingchelated soak can be removed from the surface by rinsing 40. The chelatecan then be removed from the rinsed off solution via a separationtreatment 42 and then disposed 44. The disposal 44 may includecontainment, or, separation of the mercury and phytic acid 36 aspreviously described. The result is a clean surface 46 substantiallyfree of the heavy metal.

In one embodiment, an exemplary surface treatment modality constitutes askin cream, that may be applied to workers who have contact withpollutants, especially those that contain heavy metals. A mining waste,an exploding bullet, or a nuclear power or warfare event may producevarious uranium and other heavy metal derivatives, which can be chelatedand rendered harmless or manageable by various exemplary binding agentsdescribed herein.

Submarine Water Filtration Embodiment

The exterior surfaces of submarines are known to be collectors of heavymetals such as mercury. Because fresh water is needed onboard thesubmarine, seawater is often collected into the submarine via acontaminated exterior surface and the seawater processed to removesalts. This submarine water collection and desalination is a well-knownand well-understood process. A problem with bringing seawater throughthe hull of the submarine is that the heavy metal contaminated surfaceof the submarine acts as a concentrator for the heavy metals and alsocontaminates the water to be processed for consumption within.

FIG. 3 shows an exemplary system for removing mercury and heavy metalsfrom the inlet water of a submarine. Exemplary submarine filtrationassembly 50 is comprised of a submarine hull 52, which has an outersurface 54. Outer surface 54 contains an amount of mercury that alsocombines with seawater being collected to produce contaminated seawater55. The contaminated seawater 55 enters the submarine through an inlet56.

In one implementation, a chelating filter 60 intervenes to bond phyticacid to the mercury or other heavy metal contained within thecontaminated seawater 55. Chelating filter 60 may be a fabric-likematerial. An outlet 59 provides a supply of non-contaminated seawater 57with the mercury or other heavy metal substantially reduced. The outlet59 may pass the decontaminated water to conventional desalinationmethods and equipment. Also shown in FIG. 3 is an optional carbon filter58. The carbon filter 58 may absorb additional trace amounts of mercury.The two stage process may produce a cost-effective and efficient overallfiltration system for treating seawater before desalination. Chelatingfilter 60 may be removed and replaced as needed. In one implementation,the chelating filter 60 has phytic acid embedded on the material likefibers or fabric of the filter 60. In another implementation, thechelating filter 60 receives a constant flow of phytic acid solutionmeasured in ratio to the incoming seawater, and the fibers of thechelating filter 60 mix the seawater and the phytic acid solutiontogether to bind the mercury with the phytic acid.

Absorption-Prevention Embodiment

FIG. 4 shows an exemplary anti-absorption method 70 for preventingabsorption of mercury or other heavy metal by a living organism that hasingested food that has a concentration of heavy metal. Rather thanallowing the organism to digest the mercury and then trying to removethe mercury from the tissue of the body, the exemplary anti-absorptionmethod 70 intervenes by chelating the mercury prior to its digestivetransfer to the body, thus preventing absorption of the mercury into thebloodstream or intestinal mucosa.

An amount of food 72 that may contain a concentration of the heavy metal(“contaminated food”) is consumed with an amount of the ligand 74, or,near the time of consuming the ligand 74. In one implementation, theligand 74 is phytic acid. The ligand 74 is preferably in an amountsuitable for at least substantially bonding to the mercury containedwithin the food 72. The ligand 74 may be prepared in the form of amarinade or sauce directly applied to the food 72, or may be a separatesupplement such as a pill, alternate food source, or the like. Ingestion76 may provide mixing of the food 72 and ligand 74. When the food 72 andligand 74 are mixed, then chelation 78 causes the mercury or other heavymetal in the food 72 to bond to the ligand 74, thereby forming a chelate82. The chelate 82 causes food 72 containing some mercury to become aclean food 80, substantially free of the mercury. The clean food 80proceeds to normal digestion 84, while the chelate 82 proceeds to safeegestion 86 from the body. Thus, the mercury contained within food 72 ispassed through the living organism without digestion 84. Testing hasshown that chelation between mercury and phytic acid can occur at a widerange of pH levels, including acidic levels commonly found in thestomach.

Various workers and soldiers are commonly exposed to heavy metals intheir occupational environment. As a dietary component, an exemplaryligand or combination of ligands, such as a concentrated legume protein,a concentrated pulse legume protein, phytic acid, etc., can be taken aspart of a regular diet to help the body rid itself of heavy metals andother pollutants. Typically, heavy metal derivatives, e.g., fromartillery fire enters the body through the lungs or digestive tract, andare slowly broken down or bound by the liver to be passed in eliminationvia the biliary tract. However, the various chemical species can bereabsorbed along this physiological route. Thus, the exemplary ligandsprevent the harmful metals from being reabsorbed before they can beeliminated.

Mercury/Heavy-Metal Detection Embodiment

FIG. 5 shows a device for detecting and measuring the heavy metalcontent of a substance. In FIG. 5, a probe assembly 100 has a structuralmember 101 that possesses a ligand surface 102. The probe assembly 100is inserted or placed in direct contact with a contaminated object 104,so that the ligand surface 102 can bond to some of the heavy metalcontained on or within the object 104. Upon removing the probe assembly100 from the contaminated object 104, some of the heavy metal is removedwith the ligand surface 102.

FIG. 6 shows the subsequent heavy-metal measurement process associatedwith the probe assembly of FIG. 5. At block 92, the probe assembly 100of FIG. 5 is initialized by exposing the ligand surface 102 to an acidicsolution that refreshes the ligand surface for a new measurement test.Phytic acid can be used in various forms on the ligand surface 102allowing the sensor to be reused, since the sampled metals are releasedwhen the pH is lowered. The innovative probe assembly 100 is used formetal binding and release, and can also be used with other organic,environmental, and biological substances.

At block 94, the probe assembly is exposed to a contaminant, i.e., acontaminated object 104 that may have heavy metals contained on itssurface or within its interior. At block 96, the amount, level, orconcentration of heavy metals in the sample that binds to the ligandsurface 102 is measured, e.g., via such means as spectroscopic orspectrophotometric measurement of light reflection and quality of color98 or through chemical analysis, such as qualitative and quantitativeanalysis of a test solution 99 derived from the ligand surface 102.

In one implementation, the sampled amount of heavy metal on the ligandsurface 102 can be compared against known chelation rates between theheavy metal and the chosen ligand to derive an estimated amount of heavymetal actually in or on the contaminated object 104. In oneimplementation, the probe assembly 100 uses a phytic acid ligand surface102 for measuring mercury content within fish.

A Nano-based Heavy-metal Sensor

In one implementation, a nano-based sensor used for environmental tests,medical tests, and diagnostics and can be further modified to include acapability to detect and measure heavy metals, colliforms, E-coli,dissolved oxygen, nitrate and nitrites, poisons, e.g., arsenic,pesticides and fertilizers. A conventional nano-based sensor can bemodified with additional molecules to construct an exemplary innovativenano sensor. For example, the conventional nano-based sensor may besimilar to that described in U.S. Patent Application Publication No.2007/0256941 to Prasad et al., entitled, “Nano-porous membrane basedsensors,” filed Dec. 4, 2006, and incorporated herein by reference.

Example environmental sensor applications include point-of-use (e.g.,handheld) and remote sensing (e.g., ongoing sensing of the environment).The particular analytes to be detected by the exemplary sensor caninclude, for example, heavy metals, (e.g., many known forms of mercury,lead, cadmium, uranium, and iron), gases for air quality (includingpetroleum product vapors, methane, sulfur dioxide, carbon monoxide,oxygen, particulates, and nitrous oxide), water quality contaminants(PCBs, poisons such as arsenic, dioxin, bacteria, mold, algae, anddissolved oxygen), structural infestations (organically, mold andbacteria; inorganically, carbon monoxide). The exemplary sensor can alsoimplement diagnostic applications that directly relate to the effectthat these environmental contaminants have on the health of humans andanimals, including sensing HIV viral RNA, Tuberculosis bacterial DNA;Malaria and other parasite DNAs, anitibodies, and oxidative stressmarkers associated with the above etiologies.

In one implementation, an innovative construction technique adds amolecule to the surface of the exemplary sensor that acts as anintermediate to bind substances that would not otherwise bind toconventional sensor surfaces. This allows more types of substances tobind than could bind using the conventional surface chemistry ofconventional nano wells on the probes. This allows various forms ofphytic acid to chelate metals and proteins that also complex withmetals, environmental substances, and biological substances.

In one implementation, the exemplary sensor immobilizes a solid-phasechelator-binding substance that binds to the nano wells of the exemplarysensor (or other assay system). For example, polyethyleneiminepolycation can be applied to a conventional sensor surface to serve as away to bind a concentrated protein, such as a pulse legume protein,phytic acid, EDTA, etc., to the exemplary sensor surface, which can thenchelate metals or other select pollutants. Other intermediates may alsobe used, such as metaloenzymes, carboxylases, metals, salts, and nucleicsubstances for intermediate binding of specific targets.

FIG. 7 shows the above-described molecular layers 702, such aspolyethyleneimine applied to a nano-porous membrane-based sensor to bindphytic acid, which in turn binds a heavy metal for detection andquantification.

Simultaneously Measuring an Array of Substances in a Single Sample

An exemplary sensor element consists of one or more sensing sites, eachof which is sensitized to a different target substance. The system mayinclude a unique impedance measurement block for each sensing site; or,a single impedance measuring block may be connected sequentially to eachsite. For a sensor element consisting of more than one sensing site, thecalibration consists of both the characteristics of each site inresponse to its target substance and also the cross sensitivities ofeach site to the target substances of the other sites. This allows acalculation to be performed on the measurement results for themultiple-site sensor that improves its accuracy and its ability todifferentiate between multiple target substances in a single sample.

In an example implementation, the exemplary sensor can identifysubstances in whole blood and/or saliva, such as molds, heavy metalsallergens, and parasites.

Either hand-held implementations or remote monitoring implementationsare capable of real-time measurement of heavy metals in air and water.The mechanism can be similar for both, e.g., when the analysis forsubstances in air uses dissolution of the airborne substances in asolution.

Remote Monitoring System

In one implementation, an exemplary sensor system includes 1) adisposable sensor element; 2) an electrical impedance measurement block;3) a fluid sample delivery system; 4) a system controller; andoptionally 5) a remote communications block.

The disposable sensor element has the electrical characteristic that itsimpedance changes when it is exposed to a sample fluid containing atarget substance to which it has been sensitized. The change inimpedance is proportional to the concentration of the target substancein the fluid.

Different sensor elements, or sensor elements sensitized to differenttarget substances, have different impedances and relationships ofimpedance to concentration of the target substance. The characteristicsof each sensor configuration are determined by laboratory calibrationand then loaded into the system for use with sensor elements of thatconfiguration. In one embodiment, the characteristics and/or calibrationinformation is contained onboard each sensor element and isautomatically retrieved by the system controller when the sensor elementis attached to the system. In an alternative embodiment, the sensorelement contains only information identifying its type. In this case,the characteristics information is held by the system controller. Inanother alternative implementation, the information is entered by anoperator, either at the time of system configuration or at each use.

The electrical impedance measurement block contains the electricalcircuitry to connect to the sensor element and to measure its electricalimpedance. The impedance measurement block produces an output that isproportional to the impedance of the sensor element.

The output can be continuously monitored as the sensor element isexposed to the sample fluid. In one implementation, this output is inthe form of digital data; however, an analog signal, either voltage orcurrent, is also possible. Measurement of the electrical impedanceconsists of applying an alternating current (AC) signal to the sensorand determining the relative magnitude and phase of the voltage acrossthe sensor and the current flowing through it. Impedance is the totalmeasure of opposition to electric current and is the complex vector sumof resistance and reactance. Determination of parameters can beaccomplished either directly by measurement of the voltage and currentor indirectly by comparison against a known, reference, impedance. Thefrequency of the applied AC signal can be varied in order to provide anoptimum measurement configuration for sensors with differing values ofimpedance.

The system controller is comprised of a microprocessor ormicrocontroller, memory, power supply, etc. The system controllerconfigures the electrical impedance measurement block, operates a fluidsample delivery system, and presents measurement results and statusinformation to the system operator either directly via local display inthe case of a hand-held implementation; or, via remote communicationsfor a remote monitoring implementation.

In some implementations, the fluid sample delivery system draws a samplefrom a fluid to be tested and delivers the sample to the sensor element.The fluid sample delivery system can include filtering to removeparticulate contaminants that would interfere with operation of thefluid sample delivery system or with the operation of the sensorelement. The fluid sample delivery system includes the ability to flushitself of residue left from previous sampling actions before deliveringthe new sample to the sensor element.

The optional remote communications block allows the system to operate asa remote monitor. The system is designed to permit the use of remotecommunications blocks supporting a wide variety of communicationssystems. These include, but are not limited to, IEEE 802.11 (WiFi), IEEE802.16 (WiMAX), IEEE 802.15 (Zigbee), UMTS 3G Cellular, or GPRSCellular. Via the remote communications block, a remote operator canconfigure and control the system, retrieve measurement and statusinformation, and perform diagnostic testing.

Exemplary Experimental Results

In the context of preventing mercury from being absorbed in thedigestive tract of a living organism, experiments were conducted andsubjected to statistical analysis.

Phytic acid, mercury binding proteins, and/or some food components thatcontain phytic acid (e.g., filtered or processed food components thatare naturally occurring or/and concentrated that contain relatively highlevels of phytic acid or/and metal binding proteins or/and aminemolecules) when added to food (e.g., in a proportion that ranges fromapproximately 0.1% to 60% by weight of the food) will inhibit metalabsorption by complexing with heavy metals. In birds, fish, animals,mammals, etc., the resulting complex is then eliminated through thecolon. Thus, phytic acid can be used as a metal scavenger in processedfoods and drinks.

FIG. 8 shows a mechanistic action diagram for an example experiment, inwhich mercury (Hg) in the stomach or in an intestinal cavity of thedigestive system is intercepted by phytic acid (PA), thus preventing themercury from being absorbed through the lining of the digestive system.

In FIG. 8, the abbreviations mean:

-   -   PA=Free or Fiber Complex Phytic Acid    -   HM=Heavy Metal (i.e. Pb, Hg)    -   HM-X=Organometallic Compound        And the chemical binding reactions are symbolized by:        PA⁻⁶+HM⁺²→(PA)(HM)⁽¹⁻³⁾ (Complex)        HM-X+PA→(PA)(HM-X)⁽¹⁻³⁾

To test the hypothesis that phytic acid (e.g., as found in foodcomponents high in levels of phytic acid or/and metal binding proteinsor/and amine molecules) will complex with heavy metals in food inside aliving organism (or externally to the organism) and prevent metals frombeing absorbed in the organism's digestive tract, the example experimentused 44 Zebra Fish as the test population.

Prior to the study, tests were performed on concentrated (80%) splityellow pea protein, concentrated chick pea protein (40%) and phytic acidto determine if in a salt solution these substrates would bind mercury.The test indicated that substrates would bind mercury so the study wasconducted.

Methods:

Following EPA Method 7473, a total of 44 Zebra fish were randomized intofour one gallon tanks and fed an experimental or control diet for 6days. On the seventh day the fish were not fed so that any food beingdigested would have been absorbed or eliminated. The fish were fed 1.0gram of food twice a day the first day. On the second day the fish werefed 0.5 grams twice a day. On days 3-6 the fish were fed 0.5 gram once aday. This difference in feed amount occurred as a result of identifyingthe maximum amount the fish would eat a day.

The control and experimental feed was prepared using:

3 g. Cornstarch

11.2 g. Fish Flakes

9.8 g. Frozen Thawed Brine Shrimp

30 g. Water

The corn starch and water were boiled for 2 minutes then mixed with theremaining ingredients. The basic food was divided into four groups. Thestudy groups consisted of: the control (Group C), an experimental groupin which phytic acid di-sodium salt was added to the feed at 5% byweight of the fish (Group A), an experimental group in which 15 μgmercuric iodide salt per gram of food was added (Group B), and lastlyGroup D in which fish were fed the above stated amounts of mercuriciodide salt and phytic acid di-sodium salt.

The analysis was conducted by a contracted company, Northwest PacificLabs. Samples were stratified by treatment and randomly sampled. A testof atomic absorption was used to determine absorbed mercury, aftercalibrating the instrument.

Results

FIG. 9 shows a summary of experimental results between types oftreatment groups. A Kruskal Wallis Test was used to determine mean groupdifferences. Results indicate that there was a significant (asymp sig.0.012) difference between groups for wet mercury weight. The control andphytic acid only (C) group were significantly lower in mercury as seenin Table (1), below.

TABLE 1 Test Results of Mercury Absorption Across Treatment Groups TotalHg Wet Weight Type of Treatment Mean N Std. Deviation Phytic Acid 5% perwt. .0621 4 .02054 15 Micrograms Mercury .1478 4 .04118 Iodide Salt perGram Food Fish Food No Additive .0469 4 .00698 Phytic Acid 5% per wt.And .1047 4 .02100 15 Micrograms per Gram HGI2 Total .0904 16 .04661

This result was expected since neither of those groups were givenmercury. Although the two experimental groups with mercury were notsignificantly different from each other, mercury absorption was reducedby 50% in group D that included phytic acid as well as mercury whenbaselines of mercury were controlled for. It is worth noting that largedifferences were not expected in this seven day time frame because heavymetals take at least three weeks to build up.

Table (2) shows mercury total weight by type of treatment teststatistics:

TABLE 2 Mercury Total Weight by Type of Treatment Test Statistics^(a,b)Total Hg Wet Weight Fish Wt. Chi-Square 11.029 .551 df 3 3 Asymp. Sig..012 .907 ^(a)Kruskal Wallis Test ^(b)Grouping Variable: Type ofTreatment

As shown in TABLE (3), to determine if the significance between groups Band D was being underestimated, the sample was weighted to preventerrors in estimation due to the small sample size. Results indicate thatthe phytic acid and mercury group D contain significantly (Sig=0.000)less absorbed mercury than did the mercury-alone group B.

TABLE 3 Mean Comparison of Mercury Wet Weight Between Groups B and DTest Statistics^(a) Total Hg Wet Weight Mann-Whitney U 2500.000 WilcoxonW 7550.000 Z −6.157 Asymp. Sig. (2-tailed) .000 ^(a)Grouping Variable:Type of Treatment

Conclusion

Although exemplary systems have been described in language specific tostructural features and/or methodological acts, it is to be understoodthat the subject matter defined in the appended claims is notnecessarily limited to the specific features or acts described. Rather,the specific features and acts are disclosed as exemplary forms ofimplementing the claimed systems, methods, and structures.

The invention claimed is:
 1. A method of processing a food, comprising:receiving a food that contains a heavy metal or pollutant; exposing thefood to a ligand to form a heavy-metal chelate or a pollutant chelate;and separating the heavy-metal chelate or the pollutant chelate from thefood, wherein the ligand comprises one of a legume protein, a pulselegume protein, a vegetable protein, a grain protein, phytic acid, or aphytic acid derivative.
 2. The method of claim 1, wherein the heavymetal comprises one of mercury, lead, arsenic, uranium, or cadmium. 3.The method of claim 1, wherein exposing the food to a ligand furtherincludes: finely dividing the food; mixing the ligand with a fluid; andexposing the finely divided food to the ligand-fluid mixture.
 4. Themethod of claim 3, wherein exposing the food to the ligand comprisesadding an amount of the ligand to an amount of the food, wherein theamount of the ligand is in a range of between approximately 0.1% byweight of the amount of the food to approximately 60.0% by weight of theamount of the food.
 5. A method of processing a food, comprising:receiving a food that contains a heavy metal or pollutant; exposing thefood to a ligand to form a heavy-metal chelate or a pollutant chelate;and separating the heavy-metal chelate or the pollutant chelate from thefood, wherein the ligand comprises one of a legume protein, a pulselegume protein, a vegetable protein, a grain protein, EDTA, phytic acid,or a phytic acid derivative, and wherein the food being processedcomprises fish food for fish being raised in aquaculture for commercialproduction directed to human consumption.
 6. A method of processing afood, comprising: receiving a food that contains a heavy metal orpollutant; exposing the food to a ligand to form a heavy-metal chelateor a pollutant chelate; and separating the heavy-metal chelate or thepollutant chelate from the food, wherein the ligand comprises one of alegume protein, a pulse legume protein, a vegetable protein, a grainprotein, EDTA, phytic acid, or a phytic acid derivative, and whereinexposing the food to a ligand occurs within a human digestive system toprevent the food from being absorbed into a bloodstream or passingthrough an intestinal lining.
 7. A method of processing a food,comprising: receiving a food that contains a heavy metal or pollutant;exposing the food to a ligand to form a heavy-metal chelate or apollutant chelate; and separating the heavy-metal chelate or thepollutant chelate from the food, wherein the ligand comprises one of alegume protein, a pulse legume protein, a vegetable protein, a grainprotein, EDTA, phytic acid, or a phytic acid derivative, and whereinwhen the ligand is phytic acid, adding the phytic acid to the food in aone-to-one ratio with an amount of mercury in the food to preferentiallybinds the phytic acid with the mercury while sparing calcium and metalion nutrients.
 8. A method of processing a food, comprising: receiving afood that contains a heavy metal or pollutant; exposing the food to aligand to form a heavy-metal chelate or a pollutant chelate; andseparating the heavy-metal chelate or the pollutant chelate from thefood, wherein the ligand comprises one of a legume protein, a pulselegume protein, a vegetable protein, a grain protein, EDTA, phytic acid,or a phytic acid derivative, and wherein the ligand is exposed to thefood under a vacuum.